1. Field of the Invention
The present invention relates generally to a disc processing apparatus, and particularly to a disc processing apparatus suitable for automatically executing processing work such as recording information on a plurality of optical discs and printing label surfaces on those optical discs.
2. Description of the Related Art
It has been customary to automatically mass-produce CDs (compact discs) and DVDs (digital versatile discs) which become recording media products on which music and movie were recorded so that manufacturing costs may be decreased. In order to meet with such requirements, a disc processing apparatus has been proposed, in which a recording unit for writing information on an optical disc, a printing unit for printing a label surface of an optical disc and a disc conveying unit for conveying an optical disc are formed as one body and in which a series of processing work to supply unprocessed optical discs and to collect optical discs finished as recording media products can be carried out automatically (see Cited Patent Reference 1, for example).
FIG. 1 of the accompanying drawings is a perspective view showing an external appearance of an optical disc processing apparatus according to the related art.
As shown in FIG. 1, an optical disc processing apparatus 101 described in the above-described Cited Patent Reference 1, by way of example, is mainly composed of a plurality of recording units 102 for recording information on an optical disc D, an inspecting unit 103 for inspecting whether or not information is recorded on the optical disc D properly, a printing unit 104 for printing information on the label surface of the optical disc D, a stacker 105 for accommodating therein unprocessed optical discs in the stacked state, a stacker 106 for accommodating therein processed optical discs in the stacked state, a stacker 107 for accommodating therein removed optical discs, judged as defective products by the inspecting unit 103, in the stacked state and a disc conveying unit 109 using a disc holding mechanism 108 to clamp the optical disc D and conveys it among the above-described respective units. The above-described stackers 105, 106 and 107 are fixed to a turntable 110 which is rotated. A certain stacker that should be required in the processing process of the optical disc D is located just under the disc holding mechanism 108 under control. Also, the recording unit 102, the inspecting unit 103 and the printing unit 104 are provided with disc trays 102a, 103a and 104a which can be loaded into and unloaded from the recording unit 102, the inspecting unit 103 and the printing unit 104 in response to load/unload instructions.
The optical disc D located on the uppermost portion of the stacker 105 is conveyed by a disc conveying unit 109 in the state in which it is clamped by the disc holding mechanism 108 and thereby placed on the disc tray 102a. Then, the recording unit 102 effects information record processing on the optical disc D. After the information record processing by the recording unit 102 was completed, the disc tray 102a is unloaded from the recording unit 102 and the optical disc D is again clamped by the disc holding mechanism 108. The optical disc D clamped by the disc holding mechanism 108 is placed on the disc tray 103a unloaded from the inspecting unit 103 by the disc conveying unit 109. Then, it is checked by the inspecting unit 103 whether or not information was properly recorded on this optical disc D. The optical disc D, which was judged by the inspecting unit 103 that information was recorded properly, is conveyed and placed on the disc tray 104a of the printing unit 104. After the label surface of this optical disc D was printed by this printing unit 104, the processed optical disc D is collected into the stacker 106.
Cited Patent Reference 1: U.S. Pat. No. 5,734,629
It is frequently observed that optical discs tend to stuck together after a plurality of optical discs accommodated within the stacker in the stacked state was left during a long period of time. In particular, in the case of a label printer-applicable-optical disc D in which it is assumed that suitable information such as images are to be printed on the label surface of the optical disc D, as shown in FIG. 2, since a printed surface (UV (ultraviolet) protecting layer) Db is provided near a central hole Da, it is unavoidable that this printed surface Db and an arc-like spacer Dc formed around the central hole Da stick together to cause these optical discs to stick together.
If the optical discs are sticking together, then when the optical disc is removed from the stacker prior to the information record processing, it is inevitable that the disc holding mechanism 108 holds the optical discs in which a plurality of optical discs stuck together. When the disc tray 102a is loaded onto the recording unit 102 in the state in which a plurality of optical discs is placed on the disc tray 102a of the recording unit 102, the recording unit 102 will become unable to correctly execute future processing operations.